Ph Value, 6.5 - 8.4 Ph - Grundfos DIT-L Bedienungsanleitung

7.6.2 In the absence of chlorine
1. Fill a clean vial (∅24) with 10 ml of the water
0.0.0
sample and perform zero setting.
See section
2. Remove the vial from the sample chamber
and empty it, leaving a few drops in the vial.
3. Add one DPD No. 1 tablet (No 95727747)
and one DPD No. 3 tablet (No 95727750)
straight from the foil to the water sample and
crush the tablets using a clean stirring rod.
4. Add the water sample to the 10 ml mark.
5. Close the vial tightly with the cap and swirl
gently several times until the tablets are
dissolved.
6. Place the vial correctly in the sample
chamber. See fig. 3.
7. Wait for a reaction period of 2 minutes.
!
(The countdown function can be used,
see section
8. Press the [Zero/Test] key.
Zero/Test
The method symbol flashes for
O3
approx. 3 seconds.
RESULT
"RESULT" appears in the display in mg/l ozone.
7.6.3 In the presence of chlorine
1. Fill a clean vial (∅24) with 10 ml of the water
0.0.0
sample and perform zero setting.
See section
2. Remove the vial from the sample chamber
and empty it, leaving a few drops in the vial.
3. Add one DPD No. 1 tablet (No 95727747)
and one DPD No. 3 tablet (No 95727750)
straight from the foil to the water sample and
crush the tablets using a clean stirring rod.
4. Add the water sample to the 10 ml mark.
5. Close the vial tightly with the cap and swirl
gently several times until the tablets are
dissolved.
6. Place the vial in the sample chamber
correctly. See fig. 3.
7. Wait for a reaction period of 2 minutes.
!
(The countdown function can be used,
see section
8. Press the [Zero/Test] key.
Zero/Test
The method symbol flashes for
O3
approx. 3 seconds.
The display shows result 1. Note down the
RESULT
result.
9. Rinse vial and cap thoroughly. Fill the vial
with a few drops of the water sample.
10. Add one DPD No. 1 tablet (No 95727747)
and one DPD No. 3 tablet (No 95727750)
straight from the foil to the water sample and
crush the tablets using a clean stirring rod.
11. Fill a second clean vial with 10 ml of the
water sample.
12. Add one Glycine tablet (No 95727752)
straight from the foil and crush the tablet
using a clean stirring rod.
13. Transfer the contents of the second vial into
the prepared vial.
14. Close the vial tightly with the cap and swirl
gently several times until the tablets are
dissolved.
15. Place the vial correctly in the sample
chamber. See fig. 3.
6.2 Zero setting.
6.7 Countdown/reaction period.)
6.2 Zero setting.
6.7 Countdown/reaction period.)
16. Wait for a reaction period of 2 minutes.
!
(The countdown function can be used,
see section
17. Press the [Zero/Test] key.
Zero/Test
The method symbol flashes for approx.
O3
3 seconds.
The display shows result 2.
RESULT
Calculation:
Ozone (mg/l) = result 1 - result 2
7.6.4 Tolerances
0 - 0.67 mg/l: ± 0.03 mg/l
>0.67 - 1.35 mg/l: ± 0.07 mg/l
>1.35 - 2.0 mg/l: ± 0.14 mg/l

7.7 pH value, 6.5 - 8.4 pH

Start the photometer and select method.
See section 6.1 Start.
7.7.1 Important notes
1. For photometric determination of pH values, only use
Phenol red tablets (No 95727753) in black printed foil pack
and marked with photometer.
2. Water samples with a very small buffer capacity will give too
small pH values. Water samples with low values of
alkalinity-m (equals KS 4.3 < 0.7 mmol/l equals total alkalinity
< 35 mg/l CaCO ) may therefore give wrong pH readings.
3
3. pH values below 6.5 and above 8.4 can produce wrong results
inside the measuring range. A plausibility test (pH meter) is
recommended.
4. The accuracy of the colorimetric determination of pH values
depends on various boundary conditions (buffer capacity of
the sample, salt content etc.).
5. Salt error.
Correction of test results (average values) for samples with a
salt content as follows:
Indicator Salt content of the sample
1 molar
Phenol red
-0.21
The values of Parsons and Douglas (1926) are based on the use
of Clark and Lubs buffers.
1 mol NaCl = 58.4 g/l = 5.8 %
7.7.2 Measurement
1. Fill a clean vial (∅24) with 10 ml of the water
0.0.0
sample and perform zero setting.
See section
2. Add one phenol red photometer tablet
(No 95727753) straight from the foil to the
10 ml water sample and crush the tablets
using a clean stirring rod.
3. Close the vial tightly with the cap and swirl
gently several times until the tablets are
dissolved.
4. Place the vial in the sample chamber
correctly. See fig. 3.
5. Press the [Zero/Test] key.
Zero/Test
The method symbol flashes for
PH
approx. 3 seconds.
RESULT "RESULT" appears in the display as pH value.
7.7.3 Tolerance
± 0.1 pH.
6.7 Countdown/reaction period.)
PH
2 molar 3 molar
-0.26 -0.29
6.2 Zero setting.
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